(define (has-binding? env s)
    (cond
        ((not (symbol? s))
            (report-invalid-variable s)
        )
        ((null? env) #f)
        (else
            (if (eqv? (caar env) s)
                #t
                (has-binding? (cdr env) search-var)
            )
        )
    )
)


(define (report-invalid-variable s)
    (eopl:error ’has-binding? "Bad : ~s" s)
)
